I only have personal experience with 4 online companies,Biktrix,Rize E-Bike,Ariel Rider,Rad Power and i feel safe recommending Biktrix, great company great bikes.
I have a feeling your not super concerned with top speed and power so i would also suggest you go to your Local bike shop and test ride some bikes, coming from a 250 hub drive i think you will be more than impressed with some of the middrive offerings! Just understand that any company can go belly up or just stop servicing a certain model.